加减乘除验证码(java)
(1)CaptchaUtil .java
package com.durian.common.tool; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; import java.util.ArrayList; import java.util.List; import java.util.Random; import javax.imageio.ImageIO; public class CaptchaUtil { public static String[] fuhao = { "+", "-", "*", "/" }; public static int num = 0; public static String result = ""; // 生成随机算式 public static String random() { List list = new ArrayList(); Random ran = new Random(); int n1 = ran.nextInt(10); int n2 = ran.nextInt(10); String f = fuhao[ran.nextInt(fuhao.length)]; StringBuilder sb = new StringBuilder(4); switch (f) { case "+": num = n1 + n2; break; case "-": num = n1 - n2; break; case "*": num = n1 * n2; break; case "/": if (n2 == 0) { n2 = ran.nextInt(10) + 1; num = n1 / n2; } else { num = n1 / n2; } break; } sb.append(n1); sb.append(f); sb.append(n2); sb.append("="); result = num + ""; return sb.toString(); } public static void outputImage(String str, OutputStream os) { Random ran = new Random(); // 创建图片对象 BufferedImage img = new BufferedImage(100, 40, BufferedImage.TYPE_INT_RGB); // 获取画布 Graphics g = img.getGraphics(); // 设置背景 g.setColor(Color.white); g.fillRect(0, 0, 100, 40); // 写字 g.setColor(Color.black); g.setFont(new Font("微软雅黑", Font.PLAIN, 30)); g.drawString(str, 10, 40); // 随机三条线 g.drawLine(ran.nextInt(100), ran.nextInt(40), ran.nextInt(100), ran.nextInt(40)); g.drawLine(ran.nextInt(100), ran.nextInt(40), ran.nextInt(100), ran.nextInt(40)); g.drawLine(ran.nextInt(100), ran.nextInt(40), ran.nextInt(100), ran.nextInt(40)); // 4. 输出结果 // 常见的压缩格式：jpeg(有损压缩), png(无损压缩) ... try { ImageIO.write(img, "png", os); } catch (IOException e) { e.printStackTrace(); } } } package com.duri
